The invention relates to a coupling for microcomponents which microprocesses fluids, such as micromixers, micropumps, microvalves and the like, comprising a plurality of substantially plane-parallel plates, with line connections for the supply of fluid to the components to be conveyed or mixed and for the removal of the fluids.
Numerous chemical reactions require exact temperature control and intimate mixing of the components which are to be mixed. In addition, process controll is becoming increasingly important; the required elevated degree of reliability can be ensured more easily by using lower mass flow rates. Microcomponents of a wide variety of designs are able to fulfil these requirements.
The invention deals with a coupling element for microcomponents which have a plurality of plane-parallel plates which rest on top of one another and, in their surfaces which are resting on top of one another (at the interfaces thereof, contain the structures required for the necessary mixer geometry function. Due to their good thermal conductivity and ease of structuring, these plates usually consist of silicon (known as silicon wafers) and, in the interior, have a geometry adapted to the function of the microcomponent. However, the use of other, chemically resistant materials which are adapted to the conditions of use is also possible.
Owing to the limited mechanical strength of silicon, it is necessary as far as possible to avoid tensile and flexural loads on the plates. However, fitting the line connections for the supply of the components to be mixed or conveyed and for their removal presents difficulties. On the one hand, it is necessary to ensure accurate positioning with respect to the holes emerging at the plate surface; on the other hand, there is a risk that when the line connections are being fitted or when the microcomponent is being installed or dismantled unacceptable flexural loads will be introduced into the plates, in particular silicon plates, via these line connections.
Therefore, the object of the invention is to design a coupling for microcomponents of the generic type described in the introduction in such a way that the line connections can be fitted reliably to the plates while preventing unacceptable loads being imposed on the plates.
According to the invention, this object is achieved by the fact that the plates have congruent apertures, that a connection block, which is provided with the line connections, has a plurality of attachment webs which project through the apertures and a pressure plate and, on the rear side of the pressure plate, are connected to an attachment device, and that the connection block, in its bearing surface facing towards the plates, has line openings, opposite each of which there is a line hole in the top plate.
The arrangement of the line connections on the connection block prevents forces which would lead to impermissible loads being transmitted to the plates through these line connections. All the line connections are connected to the plates via the connection block and the opposite pressure plate in such a way that flexural loads are as far as possible avoided.
The accurate three-dimensional assignment to the attachment webs which is guaranteed by the arrangement of the line connections on the connection block also ensures accurate alignment with respect to the line openings in the plate. This accurate and reproducible positioning of the line connections is also ensured each time the microcomponent is dismantled and reassembled.
Preferably, the line holes lie in the plate surface between the apertures. This results in both a compact design and uniform support for the compressive forces which arise in the area of the line connections via the attachment webs which project through the apertures.
According to a preferred embodiment of the invention, each line opening of the connection block is surrounded by an elastic sealing ring. This ensures sealed connection of the line in question.
It is particularly advantageous if each line connection has a threaded hole leading to the line opening, and that the sealing ring lies between the surface of the plate and an end face of a screw line connection which has been screwed into the threaded hole.
When the screw line connection is being screwed in, the elastic sealing ring is pressed against the plate surface. This results in a sealed connection. In the process, only compressive forces, which do not constitute any risk, act on the plate surface. The inserted elastic sealing ring serves simultaneously as a sealing and spring element which allows controlled tightening of the screw line connection.